Originally Posted by F-BIRD'88
The 920's are one of the better prefered 76cc open chamber heads.
The turn out good when ported. Much better than the 882's. The ast cast ports are better and will turn out better, once ported.
A good 76cc head to start working with for a low buck blower motor.
I have a set here too that are almost done, for my blower motor project.
I just drill and roll pin the rocker studs on mine, when I port them.
The 920's actually turn out better than my infamous ported 305HO heads do.
Just with the larger low compression chamber. They need generous porting. 2.02 x 1.60 best for these.
For the supercharger you don't want to chave them any more than nessessary.
low cr is better.
No idea on the low oil pressure. What is the oil pressure at 2000 rpm with the engine fully warmed up.? That is what matters.
You don't need a lot of oil pressure at idle. As long as the oil light stays off and the lifters don;t tick its enough.
rev it up and read the oil pressure @2000-2500rpm. (warm engine)
At 2000 rpm it shows about 15 PSi, I'm actually not gonna panic too much about it, checking the oil shows it black, and super thin oil in it, so I'm gonna ditch all the lines and oil cooler, flush the oil, run some 20/50 and then see what it looks like. Zero knocks or tics at idle even with only 2-3 psi at idle....so on a side note, due to some budgetary concerns, I may not be able to swing the blower this summer, which sucks....but is reality sometimes...I suspect braces for my kid will take priority.....that being said, what I have laying around currently is the 920 heads on the motor now, a set of 882's with screw in studs and guide plates, 70cc chambers and 202/160 valves. I have a b&m 3000 stall, I have a performer rpm intake, and a Holley 750 or an edelbrock 650,. I will be picking up a set of 410's for gear. Help me screw something together that will at least be able to turn these giant Mickey Thompson's and run a decent number, and yah I now it shouldn't matter but something that sounds lumpy would be OK too lol....yes, I do have a comp mother thmpr cam sitting on the shelf as well as a standard thumpr, one was my mistake, the other a friends mistake....so.....what can I do with this junk and still have some balls?